post_preview(): string

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Return value

string

URL to redirect to show the preview.

Performance profile

How much work a call to post_preview() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via get_post().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

46–121

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 129.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• querycontent queryget_post()called directly
• hookthird-party callbacksapply_filters()one call below post_preview()

Further down the call graph this can also reach option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 72 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost post_preview() can have, taken from its control-flow graph on PHP 8.5.

Uses · 12

• get_post()Retrieves post data given a post ID or post object.
• wp_die()Kills WordPress execution and displays HTML page with an error message.
• __()Retrieves the translation of $text.
• current_user_can()Returns whether the current user has the specified capability.
• wp_check_post_lock()Determines whether the post is currently being edited by another user.
• get_current_user_id()Gets the current user's ID.
• edit_post()Updates an existing post with values provided in `$_POST`.
• wp_create_post_autosave()Creates autosave data for the specified post from `$_POST` data.
• is_wp_error()Checks whether the given variable is a WordPress Error.
• wp_create_nonce()Creates a cryptographic token tied to a specific action, user, user session, and window of time.
• sanitize_key()Sanitizes a string key.
• get_preview_post_link()Retrieves the URL used for the post preview.

Source code

View on Trac ↗View on GitHub ↗

2065function post_preview() {2066 2067	$post_id     = (int) $_POST['post_ID'];2068	$_POST['ID'] = $post_id;2069 2070	$post = get_post( $post_id );2071 2072	if ( ! $post ) {2073		wp_die( __( 'Sorry, you are not allowed to edit this post.' ) );2074	}2075 2076	if ( ! current_user_can( 'edit_post', $post->ID ) ) {2077		wp_die( __( 'Sorry, you are not allowed to edit this post.' ) );2078	}2079 2080	$is_autosave = false;2081 2082	if ( ! wp_check_post_lock( $post->ID ) && get_current_user_id() === (int) $post->post_author2083		&& ( 'draft' === $post->post_status || 'auto-draft' === $post->post_status )2084	) {2085		$saved_post_id = edit_post();2086	} else {2087		$is_autosave = true;2088 2089		if ( isset( $_POST['post_status'] ) && 'auto-draft' === $_POST['post_status'] ) {2090			$_POST['post_status'] = 'draft';2091		}2092 2093		$saved_post_id = wp_create_post_autosave( $post->ID );2094	}2095 2096	if ( is_wp_error( $saved_post_id ) ) {2097		wp_die( $saved_post_id->get_error_message() );2098	}2099 2100	$query_args = array();2101 2102	if ( $is_autosave && $saved_post_id ) {2103		$query_args['preview_id']    = $post->ID;2104		$query_args['preview_nonce'] = wp_create_nonce( 'post_preview_' . $post->ID );2105 2106		if ( isset( $_POST['post_format'] ) ) {2107			$query_args['post_format'] = empty( $_POST['post_format'] ) ? 'standard' : sanitize_key( $_POST['post_format'] );2108		}2109 2110		if ( isset( $_POST['_thumbnail_id'] ) ) {2111			$query_args['_thumbnail_id'] = ( (int) $_POST['_thumbnail_id'] <= 0 ) ? '-1' : (int) $_POST['_thumbnail_id'];2112		}2113	}2114 2115	return get_preview_post_link( $post, $query_args );2116}

Changelog

Introduced in 2.7.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.7.7 tag, from src/wp-admin/includes/post.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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